What is the start and end date of a Cycle Count?

Hello -

Can someone explain to me the calendar/cycle of a Cycle Count.  What is the begin date and end date the the "counts per year" are based on?  I don't see this info defined as part of the Cycle Count Header.  Is it when the count is re-initialized?  Is that when the cycle count starts?  I've tested re-initialization and i don't see any evidence in the cycle count entries table that history is deleted.  And what happens when an inventory item is added mid-cycle?  I've been reading through Oracle's documentation and troubleshooting guides on MOS but there is no clear documetnation